A liquid crystal display (LCD) displays information using electrical and optical properties of liquid crystals injected into a liquid crystal panel. Compared to CRTs, LCDs have notable advantages in that they are smaller and lighter, and in addition to having low power consumption, they require low driving voltages. Due to such advantages, LCDs have wide applications in portable computers, desktop computer monitors, monitors of high-quality image display devices.
Generally, LCDs include a liquid crystal panel assembly and a backlight assembly. The liquid crystal panel assembly has a liquid crystal panel formed by injecting liquid crystals having dielectric anisotropy into a space between a first substrate and a second substrate, a driving integrated circuit (IC) mounted on the liquid crystal panel by a chip-on-glass (COG) and supplying corresponding driving signals to gate lines and data lines arranged on the liquid crystal panel, a printed circuit board transmitting pre-determined data and control signals to the driving IC, and a flexible printed circuit board connecting the printed circuit board to the driving IC. The liquid crystal panel assembly is combined with the backlight assembly which has a lamp assembly and various optical sheets, thus completing the LCD.
In conventional LCDs, a black matrix, color filters, an overcoat layer for planarizing a surface of the color filters, and a common electrode are sequentially formed on an insulating substrate provided on a second substrate, the common electrode on the insulating substrate provided on the second substrate changing the orientation of molecules in a liquid crystal layer by a potential difference from a pixel electrode provided on a first substrate. Here, the color filters may be arranged in a stripe shape, a mosaic shape, a delta shape, a square shape, or the like. In the case of forming color filters in a stripe shape, the respective color filters are formed at openings present in the same line. Alternatively, the respective color filters may be formed at openings on the black matrix in an island shape.
FIG. 1 is a layout view of a portion of a second substrate of a conventional liquid crystal display (LCD) illustrating an exemplary embodiment of color filters formed in a stripe shape.
An overcoat layer and a common electrode are sequentially formed on the color filters, or island arrangement, and column spacers are formed on the common electrode for maintaining a uniform cell gap between the first substrate and the second substrate. As described above, after forming the column spacers, the first substrate and the second substrate are combined, thus completing the liquid crystal panel.
When combining the first substrate and the second substrate, a sealant is applied to the edge of the first substrate, a liquid crystal material is dispensed into an edge portion, and the first and second substrates are aligned to then be combined.
In the course of dispensing liquid crystal into the first substrate, an excessive amount of liquid crystal may be dispensed. In such a case, excess liquid crystal may move toward the edge of the liquid crystal panel, resulting in an increase of a cell gap between the two substrates along the edge of the liquid crystal panel. That is, the column spacers are overlapped with the black matrix, the color filter layer, the overcoat layer and the common electrode on the second substrate. In addition, the column spacers are formed to a uniform height. In the case where the first and second plate are combined, an excessive amount of liquid crystal moves toward the edge of the liquid crystal panel, increasing a cell gap at edge portions of the liquid crystal panel, which eventually results in having a liquid crystal layer with uneven thickness.
As described above, if the thickness of the liquid crystal layer is not uniform, light is non-uniformly transmitted through the liquid crystal layer, which results in decreasing the manufacturing yield.
Thus, there is a need to prevent the change in the cell gap at the edge portion of a liquid crystal panel when excessive liquid crystal is dispensed into the liquid crystal panel.